Process and device for ascertaining the correct exposure for copying rows of pictures on film-bands



A. SCHULZE. PROCESS AND DEVICE FOR ARSCERTAINING THE CORRECT EXPOSURE FOR COPYING ROWS OF PICTURES 0N FILM BANDS.

Patented Aug. 9,1921.

N I] I 9 1 I N 0 H I Wu" .J D l|! m m H F n H m T m, H l 1 w n n n MI E 2 i f I I .Ioll. ll I I" e 10 U 1 I a. fi I 1 u I n P s 1K 3 I E 1 A .I l n for high lights,'and is foggy in its shadow be chosen light, are produced on of which a number,

pictures are'prod-uced not by equal volumes UNITED STATES PATENT OFFICE.

ARTHUR soEULzE, or rennin, GERMANY, ASSIGNOR or ONE-HALF 'ro nnurscnn Licn'rBI n-oEsnLLscHArr .-v., or BERLIN, GERMANY.

PROCESS AND DEVICE FOR ASCERTAINING THE CORRECT EXPOSURE FOR COPYING ROWS PICTURES ON FILM-BANDS.

citizen of Germany, residing at Berlin,

German have invented certain new and useful mprovements in Processes and Devices for Ascertaining the Correct Exposure for Copying Rows of Pictures on Film- Bands, for which I have filed applications in Germany on October 14, 1918, under Sch. 53920 VI/57o, and on August 9, 1919, under D36,258 VI/57b, and of which the following is a specification.

This invention relates to a process and apparatus for making trial photographic pictures for ascertaining the correct time of exposure for the copying of rows of pictures on film bands in copying apparatus.

In these cop ing apparatus the positive and negative lms, while in contact, are caused to move continuously, or step by step, past an exposure aperture, and the volume of light required negative film.

umeof light, while a negative which is heavy portions has to of light.

It is well known in the art to vary the volume of light thrown onto a film b changing the velocity of the movement of t e contacting films in the copying apparatus, and also to change the intensity of a glow-lamp or the like, used in the apparatus.

The q estion which volume of light should v for the particular negative, must be decided as accurately as possible by a person skilled in judging negatives. The accuracy of the expertsestimate is generally checked by a subsequent test, which generally consists in copying about a foot of film with the estimated volume of light,

be copied with-a large volume whereby about fifteen individual pictures, all

of which are subjected to equal volumesof the film band.

resent invention is to (I apparatus by the aid say fifteen, individual The object of the provide a process an Specification of Letters Patent.

Sononzn, a

varies in accordance with the density of the very thin negative necessitates a small volresponding to the number of different volumes of light for which the copying apparat'us is constructed.

From such atrial length of film it may at once be seemwhich of the exposures or volumes of light must be chosen to obtain a good positive.

In carrying out the process according to the present invention an apparatus similar to a photometer is used, adapted to th special requirements of the case.

'IVhile hotometers of the ordinary type are used or testing the sensitiveness of layers for observing the progress of a copying process such as the pigment printing process that cannot be checked by any other means, the photometer adapted for the purpose under consideration is to be used for actual pr nting, and even for printing a whole series of successive individual pictures, each of which is subjected to a difi'er- A ent volume of light.

' A constructional form of the invention is shown in the drawings, in which- F1gure 1 is a sectional elevation of a device used for carrying out the process according to my invention, and

Fig. '2 is a corresponding plan View.

Fig. 3 is a side elevation of the upper part of the apparatus.

Patented Aug. 9, 1921.

Application filed January 20. 1920. semi No. 352,848.

Fig. 4 is a plan section on the line 4-4: of

Fig. .1.

Fig. 5 is a view of the diaphragm, and F i .6 is a view of the glass plate on which the lm strips are laid and which bear the numbers to be printed on the individual pictures.

At the bottom of a rectangular box a is an electric glow-lamp b with a long incandesscent metallic filament '0. A long rectangular box d is arranged'to be placed upon the box a. By means of sixteen metal strips e fitting into corresponding grooves in the sides of the box 61 fifteen parallelepipedal which are closed at the, top by a glass plate (see Figs 1 and 6) and partially closed at the bottom by a diaphragm 9 (see Figs. 1, 4: and 5). The div cells are formed,

phragm has slots corresponding in number to the number of cells, the relative widths of these slots being as ava- The glass plate f is blackened or has dark paper glued to it; but above each tubular cell two rectangular areas are left transparent so that altogether two rows, each having fifteen transparent areas, are formed. The fifteen transparent areas of each row are numbered consecutively from 1 to 15. The distance between every two adjacent metal stripse is equal to the height of each individual picture of a film. The width of the box (Z is such that two film bands can be copied beside each other simultaneously.

At the left and right hand ends of the top of the box (ii there are two narrow hinged fiaps 7: and beside them two other narrow flaps Z. Between the flaps Z a broad flap m is arranged. The bottom surfaces of all the flaps is, Z, m, may be covered with velvet or the like, and are pressed by their weight (or by springs) against the up er surface of the box (Z, but they may a so be kept raised.

Each transparent area in the glass plate is as wide and as high as an individual picture. Journaled at the side of the box a are two film reels it (see Figs. 1 and 2) upon which the negatives to be copied are wound. The flaps in, Z and m are now all raised and the two film strips 2' to be copied are wound off the reels h and placed beside each other on the box cl or on the glass plate f in such a manner that the individual pictures to be copied lie above the unobstructing areas in the glass plate f. The two flaps I: are thereupon turned down so as to hold the two film bands 2' in position. Two positive films n, corresponding in length to the negatives, so as to register with them, aresecured in position by turning down the flaps Z. Finally.

the large flap m is also turned down. Arranged beside the box a is an electric time switch of any of the known types employed for lighting stairs for a certain in terval of time; switching off the light automatically when this interval has expired. The electric current traverses the wires 32 and g, the time switch 0, the wires 7 and s and the glow-lamp b. By pressing the but- "i ton t, the glow-lamp b is switched into circuit. and when the time for which the time switch is adjusted, say three minutes, has expii f 'ed. the current is automatically switched O Thus in each film strip fifteen pictures situated one beside the other are exposed for the same period of time (say 3 minutes) but to different intensities of light. The brightness of the light thrown onto each individual picture depends upon the width of the slot in the dia hra o osite to the film because, as indic i t b bg the broken lines in Fig. 1, each point of the particular picture in question receives light rom a portion of the filament of the glow-lamp whose length is proportional to the breadth of the corresponding slot in the diaphragm. In copying the negative the numbers 1 to printed on the glass plate are also reproduced on the positive. WVith these fifteen trial pictures it is very easy to determine the manner in which the copying apparatus used for the exposure of the positive film must be regulated.

In a copying apparatus the volume of light thrown onto the film is a product of the intensity of the light used and the time of exposure. Both of these factors are variable. The brilliancy of the glowlamp may be reduced by a rheostat. The time of exposure depends on the speed of operation of the mechanism that moves the films. By a suitable variable resistance or rheostat the speed of travel of the mechanism may be slowed down so as to increase the time of exposure of the film.

As a rule, there are eightv different values of brilliancy or light intensity of the lamp, and eight values of the speed of travel of the mechanism, and from the usual combination of these values fifteen different li ht volumes are caused to affect the positive film. There is no difficulty for any person skilled in the art to proportion the light volumes of the fifteen steps of the copying apparatus so as to agree with or have a proper relation to the light volumes used in the photometer, and vice versa so that, for instance, the trial picture 5 corresponds to the light and velocity combination 5 of' the copying apparatus.

My invention overcomes many other difiiculties in printing positive films. By producing an additional trial row of lctures it is possible to determine what vo ume of light will produce the best result if another developer or a different time of development is employed. I

An answer can also be found to another question which is not always easy to solve. That is: whether in the case of a weak negative a better result is obtainable by interposing a e yellow plate than without a yellow late.

p To facilitate the production of such supplementary trial rows, it is advisable to combine two or three of the afore-described contrivances, which must be perfectly similar in all respects and enable two or three trial rows to be produced simultaneously, i. 6., with the same source of li ht.

Photometers based on 0t er principles may also be adapted for the purpose set forth minating' said films,

for ascertaining gosu'res, for'copying a for securing the positive film a source of light for illu-.

to make all of the fifteen trial ictures mentioned. It will generally an cc to copy a short stri of film with six to eight pictures. The num er may be c0 ied along with the pictures.

In a mo ified process the different individual pictures that are subjected to dlfierent may be copied one after this enables the trial pictures to be produced in the actual copying. ap aratus by which the positive films are final y produced.

It will be obvious that many changes or modifications may be made without departing from the scope and spirit of the invention. I I

I claim-'- p 1. A process for producing trial ictures the correct time o exposrow of pictures on a in exposing an unexrough a negative band -film bearing a plurality of pictures side by side to different quantities of li ht for the different pictures for an interva of time.

2. A process for producing trial prints for determinin the exposureto be given negative films, w ieh'compri'ses, exposing through a negative film havmg a (plurality of pictures, a contacting sensitize film to be prlnted, to simultaneous illumination from the ures for copying a film band consistin posed positive film t same source but differing in quantity for each icture.

3. pparatus :for producing'trial pictures for ascertaining the correct time of ear-,- row of pictures on a 1m band, compr1s1n% a holdin device for securinga negative lm, a ho ding device in contact with said negative film,

a tube photometer bedenoting, each volume of light tween said scource of light and film holding means and a time switch whereby the li ht may be switched on and then automatic y switched ofi after the expiration of a predetermined time.

A. An apparatus for producing trial pictures for ascertaining the correct time of ex osures for copying a row of pictures on a lm band, comprising a box, an elongated filament lamp in said box, a time switch for said lamp, a negative film holding means, means for holding a positive film 1n printingcontact with the said negative film, sep arate light channels for directing the beams of the said lamp to different areas of the negative film, and a diaphragm with slots of difierent sizes interposed betweenthe said lamp and the films.

5. An apparatus for producing trial pictures for ascertaining the correct time of explosure's. for copying a row of pictures on a 1m band, comprising a box, separate light channels in said box, an op a transparent area for each 0 nels, means to hold a sensitizedfilm in printing contact witha negative film whose pictures separately register with said areas, a diaphragm having a different sizedslot for each of the said light channels, an electric metallic-filament lamp for throwing light through the said. slots, plates, and negatlve film; and a time switch whereby the li ht ma be switched on, and then automaticfily switched off after the expiration of 'a pie determined time.

ue plate having the light chan In. testimony whereof I have signed this specification in the ipi'fsence of two witnesses.

THUR

, SCHULZE. Witnesses;

' Anon! Gnosn,

L. Baron. 

